<html>
    <head>
        <title>fkjdsjafkj</title>
        <style>
            .c1{color: blue}
            .c2{color:red; width: 200px}
            .jiafa{width: 20px}
        </style>
        <script>
            function jisuanyixia() {
                var jiafa1 = document.getElementById("jiafa1").value;
                var jiafa2 = document.getElementById("jiafa2").value;
                document.getElementById("jiafa3").value = parseInt(jiafa1)+parseInt(jiafa2);
            }
        </script>
    </head>
    <body>
        <div class="c1">abcd</div>
        <img width="200px"src="html5.jpg" alt="到百度首页" title="到百度首页"><h1>我的第一个标题</h1>
        <p width=10px>我的第一个<br/>段落。</p>
        <div style="width: 50px">divdivdivdivdivdivdivdivdivdivdivdivdivdivdivdivdivdivdivdivdivdivdivdivdiv</div>
        <a href="https://www.baidu.com" target="_blank" class="c2">百度</a><br/>
        <button onclick="alert(123)">注册</button><br/>
        <table border="20">
            <tr>
                <td>1</td>
                <td>1</td>
                <td>1</td>
                <td>1</td>
            </tr>
            <tr>
                <td><button>111</button></td>
                <td>2</td>
                <td>2</td>
                <td>2</td>
            </tr>
            <tr>
                <td>3</td>
                <td>3</td>
                <td>3</td>
                <td>3</td>
            </tr>
        </table>
        <input id="jiafa1" class="jiafa" />+<input id="jiafa2"  class="jiafa"/><button onclick="jisuanyixia()">=</button><input id="jiafa3"  class="jiafa"/>
    </body>
</html>